Hypothermia and low-grade fever mean the same thing and there is not much difference. A normal person’s body temperature is relatively constant, with a small range of fluctuation throughout the day, usually no more than 1 degree. The normal measurement of oral temperature is 36.3 to 37.2 degrees; axillary temperature is 36 to 37 degrees; rectal temperature is 36.5 to 37.7 degrees. What is commonly referred to as body temperature is usually the axillary temperature. Fever, also known as fever, refers to a higher than normal body temperature. Fever is categorized into four types based on the level of temperature: low fever, moderate fever, high fever, and ultra-high fever. Hypothermia, also known as low fever, refers to a body temperature of 37 to 37.5 degrees; moderate fever is 37.5 to 39 degrees; hyperthermia, also known as high fever, is between 39 and 40 degrees; and in ultrahigh fever, the body temperature is above 40 degrees.